DRBD9.0 + RHEL 7.4

http://docs.linbit.com/docs/users-guide-9.0/#ch-pacemaker

安裝說明：
 - RHEL 7.4 (crhel71,crhel72)
 - drbd 9.0.9-1
 - 2臺相同配置服務器，硬盤數量、大小相同
 - 設定兩節點間 ssh 免密登陸
 - 使用/etc/hosts 或者DNS，讓兩個節點能互相解析
 - 設定 YUM repo, 指向到清華大學開源鏡像服務器( https://mirrors.tuna.tsinghua.edu.cn/elrepo/elrepo/el7/x86_64 )
 - 上述條件知足後，一條命令就完成安裝
     # yum -y install drbd90-utils kmod-drbd90

    
下面主要講解具體設定：

1. /etc/drbd.conf文件無需該動

2. /etc/drbd.d/global_common.conf，在common配置部分的net選項中添加protocol C;，表示使用協議C的方式進行數據複製
# sed -i "55a\                protocol C;" /etc/drbd.d/global_common.conf

# cat /etc/drbd.d/global_common.conf
...
common {
    net {protocol C;}
}

3.該文件用於定義drbd鏡像資源
# cat <<EOF> /etc/drbd.d/r0.res
resource r0 {
  protocol C;
  disk /dev/sdb;
  device /dev/drbd0;
  meta-disk internal;

  syncer {
    verify-alg sha1;
  }
  net {
    allow-two-primaries;
  }

  on crhel71 {
    address 10.247.15.78:7789;
  }
  on crhel72 {
    address 10.247.15.76:7789;
  }

  disk {
    resync-rate 100M;
    c-min-rate 10;
    c-max-rate 400M;
  }
}
EOF

4. 對節點的drbd操做, 在兩個節點上都執行：
Now that we have the configuration in place, it’s time to initialize our data:
At this point, we’re ready to start DRBD on both nodes and bring the r0 resource up. After bringing the resource up, let’s check the status:

[root@crhel71 ~]# drbdadm up r0
initializing activity log
initializing bitmap (672 KB) to all zero
Writing meta data...
New drbd meta data block successfully created.
[root@crhel71 ~]# drbdadm status
r0 role:Secondary
  disk:Inconsistent
  crhel72 role:Secondary
    peer-disk:Inconsistent

[root@crhel72 ~]# drbdadm up r0
[root@crhel72 ~]# drbdadm status
r0 role:Secondary
  disk:Inconsistent
  crhel71 role:Secondary
    peer-disk:Inconsistent

5. 選定primary node, 並同步數據

>>在全部節點中， 選定1臺做爲primary node，執行下面命令，數據同步開始進行；讓子彈飛一會，進度使用下面命令查詢
[root@crhel71 ~]# drbdadm primary --force r0

[root@crhel71 ~]# drbdadm status
r0 role:Primary
  disk:UpToDate
  crhel72 role:Secondary
    replication:SyncSource peer-disk:Inconsistent done:15.21

[root@crhel72 ~]# drbdadm status
r0 role:Secondary
  disk:Inconsistent
  crhel71 role:Primary
    replication:SyncTarget peer-disk:UpToDate done:20.35

>>幾分鐘後，在各節點上查詢狀態，看到已經同步完成：
[root@crhel71 ~]# drbdadm status
r0 role:Primary
  disk:UpToDate
  crhel72 role:Secondary
    peer-disk:UpToDate

[root@crhel72 ~]# drbdadm status
r0 role:Secondary
  disk:UpToDate
  crhel71 role:Primary
    peer-disk:UpToDate

6. 創建文件系統(do this on primary node)
[root@crhel71 ~]# mkfs.xfs /dev/drbd0

7. 測試drbd鏡像

[root@crhel71 ~]# mount /dev/drbd0 /mnt/
[root@crhel71 ~]# touch /mnt/file{1..5}
[root@crhel71 ~]# drbd-overview
...
 0:r0/0  Connected(2*) Primar/Second UpToDa/UpToDa /mnt xfs 21G 33M 21G 1%
[root@crhel71 ~]# umount /mnt
[root@crhel71 ~]# drbdadm secondary r0

[root@crhel72 ~]# drbdadm primary r0 [root@crhel72 ~]# mount /dev/drbd0 /mnt/ [root@crhel72 mnt]# ls file1 file2 file3 file4 file5